"Air Farce One" played out over lower Manhattan yesterday -- in a terrifyingly bizarre military photo op that sent office workers fleeing from their buildings fearing a new 9/11-type attack.

But it turned out that the backup Air Force One jet and the fighter that appeared to be pursuing it only 1,000 feet above Ground Zero were staging the spectacle to get publicity shots of the presidential plane with a New York backdrop.

"We all ran to the window, and I thought, that's it, we're all dead," said Chris Biancamano, 36, who works at a brokerage in Jersey City. "It brought back all the memories of 9/11. I said, 'I have to get out of here now!' "

The planes flew over the Verrazano Bridge, buzzed Lady Liberty's left ear, continued up the Hudson past Jersey City and then circled back toward Staten Island, federal officials said. The jets then completed two more loops as photographers aboard the F-16 took the world's most expensive snapshots.

Although the Air Force had permission for the 10 a.m. flyover, no one bothered to warn the people on the ground, and as the two jets hurtled toward lower Manhattan, many mistook Obama's plane for Osama's.

President Obama himself was not in the plane at the time, but the 747 flew so low that New Yorkers had no trouble reading the aircraft's insignia.

Dominick Caglioti, who works at the Mercantile Exchange in lower Manhattan, thought the planes were headed straight for his window. After learning it was all a photo op, he fumed.

"It's so stupid because they tell you about every fire drill, but they didn't tell us about this," he said.

Jillian Pizzarello, who also works at the Mercantile Exchange, said, "You don't do this to people down here after all we have been through."

Thousands of people were evacuated from buildings on both sides of the Hudson during the half-hour episode.

Federal aviation officials had notified Mayor Bloomberg's office -- but not the mayor himself -- and the NYPD last week. But officials were given clear instructions not to share the classified mission with the public, sources said.

NYPD brass told 911 operators in advance to explain to callers that the planes -- which came within 500 feet of the Statue of Liberty's torch -- were conducting an "authorized" military operation.

The only relatively high-ranking person in the Bloomberg administration told of the plan was Marc Mugnos, the director of operations in the Office of Citywide Event Coordination -- a man normally charged with approving street fairs, sources said.

Bloomberg said he never received word of the plans, and he was "furious."

"Why the Defense Department wanted to do a photo op right around the site of the World Trade Center catastrophe de fies imagination," he said. "Poor judgment would be a nice way to phrase it. Had I known about it I would have called them right away and asked them not to." Mugnos was reprimanded for failing to notify the mayor, a source said.

It's unclear how much the stunt cost taxpayers, but officials said earlier this year that flying Air Force One comes with a $40,000-per-hour price tag.

At first, White House press secretary Robert Gibbs dismissed complaints and said he had no knowledge of the flyover.

"I was working on other things. You might be surprised to know I don't know every movement of Air Force One or what happens to it," he said.

But Louis Caldera, director of the White House Military Office, later said he approved the mission.

"I take responsibility for that decision. While federal authorities took the proper steps to notify state and local authorities in New York and New Jersey, it's clear that the mission created confusion and disruption," he said. "I apologize and take responsibility for any distress that flight caused."

Obama did not know of the elaborate plans for the photos.

"When he found out, he was absolutely furious," a White House aide told The Post.

The new photo of the plane with the Statue of Liberty was to replace the current publicity shot of Air Force One above Mount Rushmore.